Preparation

1. Preheat oven to 400°F and preheat a large skillet over medium-heat. Prepare a large baking sheet by lining it with parchment paper for easy cleanup.
2. Prepare the pork: In a small bowl, make the dry rub. Combine garlic powder, onion powder, kosher salt, dried rosemary, dried thyme, paprika, black pepper, and cayenne pepper (if using). Mix well.
3. Pat pork tenderloins dry with paper towels. Divide 2 tablespoons of oil (about half) between the 3 tenderloins. Make sure they are well-coated with oil so the seasoning sticks. Then coat generously on all sides with the seasoning mixture.
4. Add the remaining 2 tablespoons of olive oil to a hot pan. Brown the tenderloins in the pan, rotating every 1.5 – 2 minutes until all sides are golden brown, about 6-8 minutes total. You may need to work in batches to avoid overcrowding the pan. Overcrowding the pan will cause the pork to steam instead of sear.
5. Transfer the browned tenderloins to the prepared baking sheet. Pour the orange juice onto the baking sheet around the pork.
6. Roast in the preheated oven for 18 to 20 minutes, or until an instant-read thermometer inserted into the thickest part of the tenderloin reads an internal temperature of 145°F.
7. Remove pork from the oven and transfer to a cutting board. Tent with aluminum foil and let rest for 10 minutes. Reserve the pan drippings from the baking sheet.
8. While the pork rests, prepare the orange pan sauce: Heat 2 tablespoons olive oil in the same skillet over medium heat. Add minced onion, chopped fresh rosemary, and salt. Cook for 3 to 5 minutes, stirring occasionally, until the onion softens.
9. Add the minced garlic and cook, stirring frequently, until fragrant, about 30 seconds to 1 minute.
10. Deglaze the pan by adding 2 cups of orange juice and the reserved orange pork drippings from the baking sheet. Scrape up any browned bits from the bottom of the pan.
11. Stir in the Dijon mustard, brown sugar, and orange zest. Bring to a simmer and cook, stirring often, until the liquid reduces by about one-third, approximately 8 to 10 minutes.
12. Slice the rested pork tenderloins into ½-inch thick medallions and arrange on a serving platter. Pour the reduced orange sauce over the sliced pork and serve immediately.

Notes

• For best results, monitor the temperature of the pork using a thermometer while it cooks. Be sure it reaches an internal temperature of 145°F for safety. The pork will continue to cook slightly while resting, so you can remove it from the oven a few degrees early.
• Fresh rosemary can be substituted with 1 teaspoon dried rosemary in the sauce if needed. Dried seasonings have a more intense flavor than fresh, so you will want to reduce the amount.